Journal of The Korean Astronomical Society (천문학회지)

The Korean Astronomical Society (한국천문학회)
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LONG-TERM VARIATION OF THE SHUTTER DELAY TIME OF Y4KCAM OF THE CTIO 1.0 M TELESCOPE

  • Lee, Jae-Woo (Department of Physics and Astronomy, Sejong University) ;
  • Pogge, Richard (Department of Astronomy, Ohio State University)
  • Received : 2016.11.02
  • Accepted : 2016.12.09
  • Published : 2016.12.31
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Abstract

We investigate the long-term spatial drift of the center and the temporal variation of the shutter delay time map of Y4KCam mounted on the CTIO 1.0 m telescope. We have collected shutter delay time maps over eight years as a part of our long-term survey program. We find that the center of the shutter delay time map can drift up to $450{\mu}m$, equivalent to ${\approx}30pixels$, on the CCD. This effect can result in a small amount of error in integration time without the proper shutter delay time correction, but it does not appear to cause any significant problems in photometric measurements. We obtain a mean shutter delay time of $69.1{\pm}0.8$ ms and find no temporal variation of the shutter delay time of Y4KCam over eight years, indicative of the mechanical stability of the shutter. We suggest that using a master shutter delay time correction frame would be sufficient to achieve high precision photometry, which does not exceed photometric errors ${\approx}1.7mmag$ across the CCD frame for exposure times longer than 1 s.

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